Hort Update for October 19, 2017

Hort Update for October 19, 2017

Nebraska Extension Hort Update for October 19, 2017
LawnsMajor Symptom:
1. Final fertilization IF needed, use fast release; apply before November 1
2. Tree leaf removal Mow them in and/or rake and recycle in compost or as mulch 
3. Mow at same height Continue to mow at 2.5 - 4 inches tall and follow 1/3 rule  
Trees & ShrubsMajor Symptom:
4. Recycle tree leaves Mow into lawn, add to compost, or use as winter mulch 
5. Wildlife protection Time to put into exclusion methods in place
6. Tree wraps Use correctly to prevent sunscald on tender barked trees
7. Pruning timing Optimum time to prune living wood is late spring into early summer
Landscape OrnamentalsMajor Symptom:
8. Plant spring blooming bulbs Still time to plant hardy bulbs - tulip, daffodil, crocus, etc. 
9. Time to dig tender bulbs Dig tender bulbs and bulb-like plants ASAP
Fruits & VegetablesMajor Symptom:
10. Sweet potato harvest & storage Harvest now to prevent cold temperature damage
11. When to prune fruit trees Best done in late February/March
MiscellaneousMajor Symptom:
12. Minute pirate bugs Tiny dark-colored biting insects; cause itchy welts
13. Fall home invaders Boxelder bugs, Asian lady beetles, millipedes, mice....
Lawns

1. Final fertilizationIF needed, use fast release; apply before November 1

IF additional nitrogen fertilization is needed in October, such as on a younger lawn, use products with quick release nitrogen and don’t apply nitrogen after mid to late-October depending on your location within Nebraska. Later applications are less likely to be taken up by turfgrass roots. They can leach out of soil or linger in soil to promote excessive spring growth. This increases mowing requirements in spring and depletes carbohydrates prior to summer. It’s essentially the same as applying nitrogen fertilizer too early in spring.  In fall, apply potassium based fertilizer only if a soil test recommends it.  Fall applied potassium has been shown to increase turfgrass susceptibility to snow mold.

Rethinking Fall Fertilization, Turf iNfo

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2. Tree leaf removalMow them in and/or rake and recycle in compost or as mulch

Rake or mow tree leaves into the turf on a regular basis to avoid build-up of leaves on lawns, which can suffocate turf or increase snow mold risk.  Mulch-mow tree leaves to add compost and nutrients to your lawn; and to cover bare soil areas where weed seed could germinate and begin growth. Pulverize leaves by using a mulching mower or making two or three passes with a regular mower. After mowing, the pulverized leaves should not cover the turf, but filter into the grass.

Mulch Leaves into Turf for a Smart Lawn, Michigan University Extension

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3. Mow at the same heightIdeal window for overseeding is or has closed; seed very soon

Continue to mow at the same mowing height (preferably between 2.5 and 4 inches) until turfgrass stops growing. A taller height can reduce weed seed germination and shade out small weed seedlings. Continue to follow the one-third rule of not removing more than 33% of the grass blade at any one mowing. Removing more than one-third is considered scalping and can weaken root systems. 

What is the Optimal Mowing Height and Frequency for Lawn-Height Turfgrass?, Turf iNfo

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4. Recycle tree leavesMow into lawn, add to compost, or use as winter mulch

Recycle tree leaves by 1) mowing them into the lawn, 2) shredding and adding to compost piles, 3) tilling into garden soil, or 4) by saving large, coarse leaves to use as winter mulch over tender plants. Fallen tree leaves, and grass clippings, are an important source of organic matter.  As this yard waste decomposes, phosphorous and nitrogen is released. This is beneficial if decomposition is taking place in a compost pile or garden bed.

If leaves fall into water, such as a lake or pond, and decompose an overload will contribute to impaired water ecology, commonly seen as excess algal growth. To reduce the pollutant load on surface water, do not dump tree leaves or grass clippings along stream banks or near ponds where rainfall and snow melt can carry them into the water.

Recycle Tree Leaves for Healthy Lawns, Gardens and Water, Nebraska Extension

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5. Wildlife protectionTime to put exclusion methods into place

Exclusion is the best means of protecting trees and shrubs from damage by rabbits and voles during winter. Now is the time to encircle the trunks of young trees with a ring of one-fourth inch mesh hardware cloth for winter protection. Avoid deep layers of mulch, deeper than two inches, around trees and do not pile mulch against tree trunks. For deer damage, use repellants according to label direction.

Managing Deer Damage in Nebraska, Nebraska Extension
Managing Rabbit Damage, Nebraska Extension
Controlling Vole Damage, Nebraska Extension 

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6. Tree wrapsuse correctly to prevent sunscald on tender barked trees

This is the time of year to prepare to wrap the trunks of young, tender barked trees, such as red maples, to protect the bark from winter sunscald. Not all young trees need to be wrapped. When tree wrap is used, only use it on 1) tender barked trees during their first winter after transplanting, 2) when moving trees, 3) or if a nursery guarantee requires it.

Wait until after a hard freeze or after leaves have dropped. On young trees, wrap covers photosynthetic tissue that produces food the plant needs for root establishment. If wrapped too early, less stored food may be produced; or moisture may build up beneath the wrap. When wrapping tree trunks, begin at the bottom of the tree and wrap upwards, being sure to overlap the wrap so no part of the trunk is exposed. Remove all wraps in early spring. If left on too long, wraps can girdle young trees; and moisture may build up beneath tree wrap to promote decay organisms.

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7. Pruning timingoptimum time to prune living wood is late spring into early summer

There is much discussion and research on when the best time is to prune trees. While trees can be pruned most anytime, there are optimum times to prune and times to avoid pruning. General recommendations on when to prune will be provided here; however, the type of tree, pests issues, and environmental conditions, also determine when the best time is to prune specific types of trees.

Previously, it was recommended the ideal time to prune most trees was during winter dormancy. New research is showing the optimum time to prune green wood or living branches is in late spring and early summer. This timing promotes the quickest and most effective recovery of pruning wounds as this is when the cells are most active during the growing season. Defense systems, known as CODIT or compartmentalization of decay in trees, and which produce boundary layers, callus tissue, and wound wood, develop and seal fastest on cuts made shortly before or early in the season of most active growth.

Dead wood can be removed most anytime, if correct pruning cuts are made.

Late summer and fall, when trees are preparing for dormancy and leaves are dropping, is one time to avoid pruning trees. Pruning at this time can promote a late flush of new growth susceptible to winter injury and delay dormancy on some trees. Late winter or early spring is still a good time to prune most trees. This leaves wound tissue exposed for a shorter period of time before sealing begins, compared to trees pruned from November through February.

Tree Pruning Essentials, Purdue Extension

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8. Plant spring blooming bulbsTime to plant hardy bulbs - tulip, daffodil, crocus, etc.

Bulbs are some of the easiest plants to grow and October is a great time to plant them. Most bulbs prefer full sun or a minimum of six hours daily. Others, such as woody hyacinths, require partial shade. Well drained soil is a must and bulbs benefit from the addition of organic matter to the soil. Organic matter loosens the soil and adds essential nutrients. Thoroughly mix compost with loosened soil at a rate of 1 part organic matter to 4 parts soil. For example, 3 inches of organic matter should be incorporated to a depth of 12 inches.

Spring Flowering Bulbs, Nebraska Extension

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9. Time to dig tender bulbsDig tender bulbs and bulb-like plants ASAP

Tender bulbs and bulb-like plants are not winterhardy in Nebraska gardens if left in the ground. Dig them up as soon as possible and provide good storage conditions, so they can be grown again next year. This includes Canna, Gladiola, tuberous Begonia, Dahlia, Caladium, Alocasia (elephant ears) and Colocasia (elephant ears or taro plants).

Check bulbs and bulb-like plant, being overwintered indoors, monthly for signs of rot or excess drying. Any residual moisture and/or disease on the bulbs when they went into storage could cause problems down the road. Discard any bulb with mold or signs of rot.  If bulbs start to shrivel, this could indicate they are becoming too dry.  Dunk them in water to rehydrate them.  Repacking them for storage with dry sand, sawdust, vermiculite or peat moss may help reduce excessive drying.

Tender Perennials Need Indoor Protection, Purdue University Extension
Storing Tender Bulbs and Bulblike Structures, University of Minnesota Extension

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10. Sweet potato harvest & storageharvest now to prevent cold temperature damage

Sweet potatoes are tropical plants and their tubers are susceptible to damage from heavy freezes, making them prone to storage rots. So it's time to harvest. Even though some areas of Nebraska have already received their first frost, light frost will kill the vines but should not damage the sweet potatoes.

Most sweet potato cultivars are ready to harvest 95 to 125 days after transplanting. Generally the vines start to turn slightly yellow when the tubers are ready to harvest. Pulling or cutting the vines 2 - 3 days before digging will toughen the skins and help reduce harvest damage. After harvest the tubers should be cured by placing them in a warm (85F), humid (90% RH) location for 4 to 6 days to increase sugar content, heal harvest damage and increase the orange flesh color.

Growing Sweet Potatoes in Missouri, University of Missouri Extension

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11. When to prune fruit treesBEST DONE IN LATE FEBRUARY OR MARCH

Wait to prune fruit trees until late February-March. The best time for pruning fruit trees for fruit production is in late winter, into early spring, depending on the weather. See the following publication for more information on fruit tree pruning.

Pruning Fruit Trees, Nebraska Extension

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12. Minute pirate bugsTINY DARK-COLORED BITING INSECTS; CAUSE ITCHY WELTS

During the late summer, small insects known as minute pirate bugs cause painful bites that seem out of proportion with their size. The minute pirate bug is about 1/8-inch long, oval to triangular in shape, flattened and black with whitish markings on the back. Normally, they are predators and feed on insect eggs and small insects. They feed by impaling their prey with their short blunt beak and sucking the juices.

Minute pirate bugs are found throughout the summer in fields, woodlands, gardens and landscapes. In the late summer, they begin the unpleasant behavior of biting humans. They do not feed on blood or inject a venom or saliva.

People differ in their response to pirate bug bites. Some people have no reaction to the bite, but others have bites that swell like a mosquito bite or turn red. Because the bite is noticeable and the pirate bug doesn't fly quickly, the victim is usually able to successfully smash the offending insect.

Control of minute pirate bugs is not practical. Repellents are generally not effective, although some people have found applying baby oil or suntan oil liberally to the skin may prevent some bites by coating the pirate bugs with oil.

Minute Pirate Bugs: Little Bugs, Big Bite, Nebraska Extension

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13. Fall home invadersBoxelder bugs, asian lady beetles, millipedes, mice...

Nuisance insects and mice enter homes in fall as temperatures cool and they begin to look for overwintering sites. Pests like boxelder bugs, millipedes and Asian lady beetles are common. Most are harmless but a nuisance.

Exclusion is the best means of reducing nuisance pests and mice indoors. Caulk cracks, crevices and conduits of the home. Repair window screens and check that doors are tight fitting. If needed, insecticides can be applied to building foundations according to label direction. Ideally, apply the insecticide from the foundation out to five to 10 feet.

Boxelder Bugs, Nebraska Extension
Centipedes and Millipedes, Nebraska Extension
Controlling House Mice
, Nebraska Extension
Identification Guide to Common Spiders in Nebraska, Nebraska Extension
Multi-colored Asian Ladybird Beetles, Nebraska Extension
Pest Proofing, Nebraska Extension

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Seasonal information for Nebraska's green industry professionals.

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  • Emerald Ash Borer Resources - EAB was confirmed in Omaha, NE 6/8/16 and Greenwood, NE 6/17/16. No additional confirmation have occurred as of 10/12/2017. It is recommended homeowners wait to begin treating their ash trees until the insect is confirmed within 15 miles of their location. 

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